Superoxide dismutases (hereinafter referred to simply as SODs) are enzymes present in a wide variety of organisms such as animals, plants and microorganisms. SODs catalyze disproportionation of the free reactive oxygen species called the superoxide anion radical. SODs are expected to be used as an antirheumatic drug, as a therapeutic agent for autoimmune diseases and myocardial infarction, during organ transplantation, for scavenging radicals generated in vivo by the use of antithrombotic agents after cerebral infarction, and for various kinds of inflammation (non-patent document 1).
Various SOD derivatives have been proposed. For example, a lecithinized superoxide dismutase (hereinafter lecithinized superoxide dismutase will be referred to as PC-SOD) with greatly improved accumulability in target lesions and greatly improved in vivo stability obtained by lecithinizing a specific SOD is proposed as a drug (patent document 1).
Patent Document 1: Japanese Patent No. 3070980
Non-patent Document 1: “Kasseisanso-no Rinsho-heno Tembo (Clinical Review of Active Oxygen)”, edited by Naoyuki Taniguchi, published by Iyaku Journal Co., Ltd., Tokyo, pp.61-111 (1994)